In furniture, especially, the arms of chairs have presented a problem accentuated by the physiological variances in persons using the chairs and in the many relative positions desired by the occupants of the chairs.
In 1988, the prior structures saw a substantial advancement as embodied in the Adjustable Armed Chair of Ralph K. Rye, the inventor herein, expressed in the prior U.S. Pat. No. 4,872,727. In that work, the inventive directions looked toward a simple parallelogram structure operating on a pantographic frame and adapted to the modern ergonometric seating with the capability of utilizing the chair back as the concealment for the structural connection and for the power element. The U.S. Pat. No. 4,872,727 made a substantive impression on the industry, but the most severe criticism was directed at the almost impossible task of maintaining clearance at the pivots or joints to assure a tight and smooth connection. In use, clearances were introduced in the journalling and no simple solutions were available in maintaining tight joints resistant to vertical and horizontal displacement.
Accordingly, the inventor sought to improve the structure by seeking the elimination of control of wear factors at the pivots and after substantial effort and expenditure of money and time, the present construction began to take shape. A rigid framing structure for the arms was devised. Within that framing or housing of the arm elements, pivots on elongate substantially sized through-bushings were located and steel cables operating on the pivots or the blocks and in guided anti-friction relation were interlaced and tensioned to perform as desired at those selected and adjustable tensions. A more stable set of adjustable arms resulted and the simple tightening of the cable yields a system under substantially constant tension, which is amendable to power actuation, field adjustment, and provides the desired quantum of structural stability. Accordingly, the principal object is to achieve a higher order of stability. A closely related object is the attainment of stability with a constant tension cable control system. A further object is appreciated in the achievement of the foregoing objects at an economical cost. Additionally, the adaptability of the invention to a wide variety of furniture styling and design in chairs is an overall object, while other uses for elevating adjustment of extended arm elements are contemplated.